Interpretive Summary: Consumer products such as cars or refrigerators may be made more energy efficient through the development and use of low viscosity bio-based oils. Scientists at NCAUR are creating new biodegradable vegetable-based lubricants and fluids from acetic- and oleic-based chemical blends called estolides. These new materials are easier on the environment than petroleum products and have equal or better low temperature properties without the use of additive packages. These new acetic-based estolides have interesting and useful low viscosities. Oils with lower viscosities need less energy to move and create less drag on an engine which translates into increased miles-per-gallon ( MPG) and cost savings. Estolides from oleic and acetic acids could help meet the demand for higher performance and lower cost, and reduce our dependence on imported petroleum-based oils.

Technical Abstract:
Acetic- and butyric-capped oleic estolide 2-ethylhexyl (2-EH) esters were synthesized in a perchloric acid catalyzed (0.05 equiv) one-pot process from industrial 90% oleic acid and either acetic or butyric fatty acids at two different ratios. This was directly followed by the esterification process incorporated into an in situ second step to provide a low viscosity estolide ester functional fluid. The dimer and polyestolides were separated via distillation at 240-250 deg C. The physical properties of these materials were followed throughout the synthetic process and are reported. The final low viscosity acetic- and butyric-capped dimer estolide 2-EH esters had viscosities of 19.9 and 24.2 cSt at 40 deg C and 4.8 and 5.5 cSt at 100 deg C with viscosity index (VI) of 161 and 163, respectively. Both dimer estolide esters displayed excellent pour points (PP) while cloud points (CP) were not determined on the final products due to the dark color of the material. The PP of the two were: acetic-capped estolide 2-EH ester (-45 deg C) and butyric-capped estolide 2-EH ester (-27 deg C). Along with expected good biodegradability, these short-capped oleic estolide 2-EH esters had acceptable properties that should provide a specialty niche in low viscosity applications.